But that's about all the parties agree on as they prepare to battle over the congressional map of Maryland.

The 1990 census figures released by the state planning office this week show that seven districts have grown in population since 1980 while one, the 7th District in Baltimore and part of Baltimore County, has lost people.

These changes require that the legislature redraw district boundaries to equalize population. When state lawmakers convene for this task in the fall, they will have the opportunity to address another population trend: the growing black population in Prince George's County.

The county now is largely contained within the 5th congressional district, which the new census figures show has 277,267 blacks and 268,411 whites. But part of the county, including a number of its black residents, is in the adjoining 4th district of Democratic Rep. Tom McMillen.

Kevin Igoe, executive director of the state Republican Party, said yesterday that the county's black population "ought to be combined in one district . . . so that the minorities have a chance to elect a minority if they want."

Democrats don't disagree, but they probably will try to revise the boundaries in ways that won't please Republicans.

For Democrats, a top goal is protecting Rep. Steny H. Hoyer, D-5th, who is white and likely to face future challenges from black Prince George's politicians if his district remains largely as it is now. Hoyer, Democrats say, is invaluable to Maryland as a member of the Appropriations Committee and head of the House Democratic Caucus.

For that reason, Democratic sources have said they are considering creating a district for Hoyer that combines a part of Prince George's County with St. Mary's and Charles counties. The rest of Prince George's then could be united with part of Montgomery County in a district that would be heavily black.

In that way, Democrats have privately suggested, they could protect Hoyer while assuring the large Prince George's black population a clear shot at electing a member of Congress.

But Republicans don't want to see St. Mary's and Charles counties stripped from the 1st District, represented by Republican Rep. Wayne T. Gilchrest. They fear the Democrats also would reconfigure the 2nd District, represented by Republican Helen D. Bentley, so that she and Gilchrest would be pitted against each other.

The Democrats haven't officially presented a plan. But Gerard E. Evans, deputy chairman of the state Democratic Party, said the census numbers "easily justify" extending Hoyer's district into Southern Maryland and creating another district out of Prince George's County and part of Montgomery County.

"You could conceivably have a district that runs from Friendship Heights to District Heights," Evans said. "Politically, I don't know if it would sell or not."

In any event, Democrats are under pressure to devise a plan that addresses the concerns of black Prince George's voters.

State Sen. John A. Pica Jr., D-City, chairman of the Senate's committee on reapportionment and redistricting, said the census numbers for the county "just about dictate that we take a close look at drawing another district for a black representative."

There is one largely black district now, the 7th, represented by the only black Maryland member of Congress, Democratic Rep. Kweisi Mfume.

Democrats conceivably could seek to bolster Hoyer by further splitting up Prince George's black voters into different districts, but that idea is unpalatable if not impossible.

"If minority groups are split up in order to protect incumbents, this plan will end up being drawn by a federal judge," Igoe warned.

Pica agreed that "there's going to be legally mandated sensitivity to the black population" under federal voting rights law.

The legislature will have the final say, after holding public hearings. Although the legislature is predominantly Democratic, Republican officials say they will try to use public opinion and, if necessary, the courts to prevent the other side from rigging the boundaries against them.

Federal law requires that districts be as close to equal in population as possible.